Update: this is how Chase answered my question on the noise level issues: "I didn't experience any unjust noise at 800 with properly exposed images. 1600 even looked nice. I ultimately might be willing to shoot the D3 at higher ISO than the D3x, but that's really transcending what the D3x is meant for... Compared to other cameras at that D3x res, even 800-1600 is a total score" (source). I do believe him.
Chase Jarvis just completed the first national ad campaign shot with the Nikon D3x. His opinion on the D3x: "I am loving it". No problems reported. You can see all of his D3x videos here.
I received a single report of a faulty D3x and it was something not related to the noise levels (I got a screenshot of the service order, so the issue was real but an isolated incident). Given the number of readers we have, I think we can conclude that Thom's problem was an unique quality assurance issue and and should not be a concern at that point.
A reader (thanks John) created a side by side comparison of D3 and D3x at various ISOs (100-1600). Check it out here: http://www.jonmccormack.com/d3x.html
Another set of D3x crops from reader: http://www.garethhacon.com/portfolio46726.html
I also got some D3x shots in the Nikon Rumors group on flickr: